: This proposal is aimed at expanding our knowledge of the psychological and physiological bases of meaning from scalp recordings of event-related potentials (ERPs) to words and pictures. Current evidence suggests that (1) the N400 indexes the influence of semantic context on word recognition: (2) P600 amplitude is sensitive to various structural manipulations; (3) the LAN is related to working memory usage; and (4) a variety of over-sentence slow potentials reflect aspects of sentential structure. The proposed experiments examine these hypothesis and use these components to address specific questions about comprehension. Specifically, the experiments focus on the degree to which sentence level semantics, pragmatics, and syntax dominate or can alter the processing of purely lexical relationships, how background knowledge is used in comprehension, and the extent to which pragmatic and lexical factors influence sentence parsing. Exp. 1 contrasts lexical versus sentence context effects in natural speech. Exp. 2 questions whether lexical/associative priming is mandatory and automatic or can be directed by the propositional content of the sentence in which the words occur. Exp. 3 examines the claim that lexical priming effects are not maintained across the clause boundary. Exp. 4-5 focus on how background knowledge in the form of word (4a) or picture (4a) categories and high level frames (5) in long term memory is used to comprehend sentences, including one-line jokes. Exp. 6 further probes the functional significance of the N400 by contrasting lexical semantic violations with those entailed in zeugma (e.g. Jim caught a fish and a cold last Thursday). Exp. 7-10 examine the role of various non-syntactic factors in sentence parsing, specifically the contributions of verb augment preferences and complementizer omission (7a), and verb argument preferences and noun plausibility (7b) on processing of sentences containing (reduced) relative clauses, and the effects of discourse factors on the processing of prepositional phrases in syntactically ambiguous contexts. Exp. 9-10 focus on the effects of the animacy of the initial noun (9) and pragmatic relations between both nouns in the processing of object relative (OR) constructions (10) on reading times as well as ERPs during reading and listening. Exp. 11 and 12 are proposals to build an database of word ERPs for exploratory analyses and to develop a procedure for recording saccades-related brain activity during free reading, respectively. Overall, they aim to determine how constraints at lexical, semantic, syntactic, and pragmatic levels of language interact in the brain to yield meaning.